6 
BULLETIN 1450, TV S. DEPARTMENT OF AGRICULTURE 
filled gravel and bowlders. It covers a gross area of approximately 
17,252 acres. The rocky dike that once turned the river has for 
many years diverted the underflow of Salt River above Tempe into 
these beds of gravel and bowlders and has kept them filled with 
T.2N. 
T.3N. 
Sa/tr?/Ver Project Boundary 
/Off. Ground-water Contour 
Area A t October, /S/<3 
mm So/7 
e=a Ctay and Cem en ted Moter/'a/s 
oaa Co/ /'che 
E53 Gra\/e/ and Bow/ders 
(£2) Sand 
I 
Fig. 4. — MaD with vertical cross sections showing formations penetrated by wells in 
area A 
water, until surface flows appear in the restricted channel of Salt 
River at Tempe and along the slope leading down to Gila River 
east of the Salt River Mountains. Recent contribution to this 
ground water by seepage from canals and irrigated fields raised its 
level until in 1913 these lands became affected by a high ground- 
